1. Field of the Invention
The present invention relates to a golf club head.
2. Description of the Related Art
Regarding a material used for a golf club head, various proposals have been conducted. Japanese Patent Application Laid-Open No. 2002-35180 discloses a golf club head using a porous metal. Japanese Patent Application Laid-Open No. 2002-126138 discloses a head in which a porous metal is disposed in a head body made of a metal outer shell in order to enhance a hitting sound and hitting feel. A view showing the relationship between porosity and an elastic modulus of a porous metal made of a titanium alloy is described in The Japan Institute of Metals (Nihon-Kinzoku gakkai), Annual autumn meeting (the 135th) outline (2004), p. 466.